1. Technical Field
The disclosure relates to a display device, more particularly to a display device and its light enhancement film.
2. Description of Related Art
A traditional electrophoretic display (EPD) has an upper substrate, a lower substrate, and an electrophoretic film arranged between the upper substrate and the lower substrate. If the electrophoretic display does not have a brightness enhancement film (BEF) arranged thereon, after external lights arrive the electrophoretic film via the upper substrate, because reflected lights from the electrophoretic film cannot be effectively transmitted outwards the electrophoretic display by the upper substrate, the light intensity of the reflected lights from the electrophoretic film for a viewer is degraded.
Therefore, the brightness enhancement film (BEF) can be arranged in the electrophoretic display to enhance the light intensity thereof, in which the brightness enhancement film (BEF) normally has a micro structural layer thereon. The micro structural layer has a plurality of microstructures. The microstructures are presented as pillars which are lain parallel and interspaced on a surface of the brightness enhancement film.
When an incident light from an external light source is transmitted into the electrophoretic display and travels to the electrophoretic film in a direction parallel to the parallel pillars, the light intensity of the electrophoretic display can be improved positively, so as to upgrade the quality of the display for the viewer. However, when another incident light from the external light source is transmitted into the electrophoretic display and travels to the electrophoretic film in another direction perpendicular to the parallel pillars, the light intensity of the electrophoretic display cannot be improved, and degrades the quality of the display for the viewer
Therefore, how to develop a brightness enhancement film (BEF) for improving the mentioned disadvantages and inconveniences shall be concerned.